Among the developments of chemistry are polymers that have been applied by the cosmetics industry to the formation of artificial fingernails. These new materials serve as adhesives for bonding plastic extensions to a wearer's fingernails. They are strong and tough and serve both as adhesives and as fillers. Some are capable of being used to build up an extension without anything more. A shield is placed under the nail so that it serves as a form for the lower surface of an extension. The nail material is painted on to the end of the user's nail and over the shield. Drying is rapid, and the result is a hard, tough, properly flexible extension.
However, the qualities that make these materials serve as fillers serve also to produce an extension of uneven thickness and length. The dried material needs to be shaped and then the hardness and toughness are disadvantages. Smoothing and shaping the new nail requires a file or sandpaper or, more usually, a grinding tool.
The underside of the new nail is easily smoothed and polished with the side of a small rotary grinder. A simple cylindrical grinding wheel is adequate because the underside of the nail curves around such a wheel. But smoothing the upper surface and trimming and shaping the end is not so easily accomplished. Here, the nail curves the wrong way and it is more difficult to smooth the edges at the side of the nail without injuring the flesh of the finger.
The difficulty in smoothing the nail, especially on the right hand of a right-handed user, or the left hand of a left-handed user, has effectively prevented women from self treatment to rebuild and extend nails, despite the ease with which the new materials can be used to build up a nail extension.
Treatment is now largely reserved to professionals. That has not diminished the need for a better smoothing apparatus and technique even in the hand of a professional, a conventional grinding tool curves oppositely from nail curvature. However, the professional is required to work fast and is expected not to grind into a client's finger in the process. The smoothing process is primarily mechanical--filing and/or grinding. To do that rapidly generates heat. The craft and hobby kit grinders that have been the manicurists' standard tool are used in a way that concentrates rather than distributes the heat. The result is often discomfort and it has been common practice to keep a container of cooling water at the manicurist's work place to remedy misjudgments. Grinding at the edge of a rotating wheel requires a relatively high degree of skill both in guiding the tool over the work area and in controlling the pressure with which the tool is applied to the nail. Grinding at the side of such a rotating wheel requires even more skill because the tendency for the tool to "walk" is increased. The invention provides an effective and practical solution to these problems.